The present disclosure generally relates to a system and method for measuring current in an electric meter. More specifically, the present disclosure relates to a system and method for measuring current in an electric meter using a reactive sensor.
Several methods are in use to measure current in an electric meter. These methods include Rogowski coils, current transformers and resistive shunts. Although each of these methods is useful in determining the amount of current flowing through an electric meter, each of the three currently available options add additional cost to the meter.
Presently, the lowest cost approach to accurately measure current in a production electric meter utilizes a resistive shunt. The amount of current flowing through the electricity meter is directed through the resistive shunt and the voltage across the resistive shunt is measured. Although this method is effective at measuring current, the resistive shunt eventually heats up and the resistance of the resistive shunt changes with the temperature change. Thus, temperature compensation is needed to overcome the effect of the change in resistance during the measurement period, which increases both the cost and complexity of the electric meter.
Additionally, in high power electric meters of 100 amps or more, the resistive shunt may dissipate too much power. While shunts of 25 micro ohms can be made to reduce power dissipation, measuring the voltage across such a small resistance is difficult and the cost of such device can be prohibitive. The present disclosure addresses many of these drawbacks of current sensing systems that are presently in use today.